This invention relates to a radiation sensitive resin composition useful as a negative type resist for producing a liquid crystal display device.
As a resist to be used in the lithographic process for producing a liquid crystal display element, there have heretofore been broadly adopted a positive type resist using a novolak resin and a quinonediazide compound and a negative type resist using a cyclized rubber and a bisazide radiation sensitive compound.
However, in the case of producing, for example, a liquid crystal display element, the proportion of the area of the wiring portion to the whole area of a substrate is small (namely, the portion remaining as a resist pattern is small), so that the positive type resist is disadvantageous in being liable to undergo the influence of dust. Therefore, the negative type resist is more advantageous. However, a conventional negative type resist using a cyclized rubber and a bisazide radiation sensitive compound requires an organic solvent as a developer, and hence, has such a problem that the working atmosphere is deteriorated. Thus, a difficulty has accompanied the application thereof to the production of a liquid crystal display element or the like on a commercial scale. Thus, a growing interest has recently been taken in a negative type resist developable with an alkali developer.
Also, in the lithographic process for producing a liquid crystal display element or the like, the surface of a substrate on which a resist pattern has been formed is treated by a chemical etching, an electrolytic etching or the like and then the resist pattern is dissolved in a stripping solution consisting of an organoalkali. Even in the case of a negative type resist, however, there has been strongly desired the development of a resist which can form a pattern having a good shape, has a high adhesion to the substrate and so high acid resistance as not to be affected by an etchant, and is endowed with so high a strippability as to be easily dissolved in a stripping solution.